The present invention relates to fire hydrants, and more particularly to locking mechanisms for fire hydrants.
It is not uncommon for municipalities or other entities to secure the water delivery valve of a fire hydrant in order to ensure sufficient pressure and volume is available in the water supply lines to fight a fire. In other circumstances, these entities may secure the water delivery valve of a fire hydrant in order to prevent the insertion of contaminants into the drinking water or theft of the drinking water, or damage to utility pipe network. While there are many other locking devices in the art, they may require modifications to the hydrant, be easily defeated with commonly available tools or are not readily removed by fire fighters when the need arises.
A first example of a fire hydrant locking device is disclosed in U.S. Pat. No. 4,736,765. A hydrant securing device is adapted for use on a conventional fire hydrant having an exposed upper valve nut and a pair of caps each formed with a cap nut. The device preferably comprises a one-piece steel yoke having a generally U-shaped configuration dimensioned for seating directly on the valve and cap nuts. The yoke has a generally horizontal base formed with an opening dimensioned for location about the valve nut, and a pair of downwardly-directed arms, each arm having an opening dimensioned for location about one of the cap nuts. The openings conform generally to the shape of the nuts and prevent rotation of the nuts relative to the yoke so that the caps cannot be removed and water flow cannot be initiated. The yoke is sufficiently resilient that the arm portions can be elastically separated to permit simultaneous location of the openings about the valve and cap nuts and to permit removal of the hydrant securing device in the event of a fire. Each arm has a strap guide formed by displacing a portion of metal from the associated arm to define a passage between the metal portion and the associated arm. A steel strap clamp is extended through the strap guide passages and crimped to prevent separation of the yoke arms and removal of the device. The strap clamp is snapped with a wrench or other prying tool when access to the hydrant is required.
A second example of a fire hydrant locking device is disclosed in U.S. Pat. No. 5,549,133. A security device and system for preventing unauthorized access to and operation of fire hydrants. The security device includes a first end portion for coupling the device to a portion of a fire hydrant. The first end portion preferably is coupled to the hydrant by clamping in between an outlet port of the hydrant and a cap for covering the outlet port. A second end portion covers a valve control device of the hydrant to control access to the valve control device and thereby prevent unauthorized persons from activating it. An intermediate portion integral with the first and second end portions extends vertically from the first end portion to the second end portion. The system for preventing unauthorized operation of a fire hydrant includes the security device described above, a bonnet for protecting a valve control device of the hydrant, and a locking cap for closing an outlet port of the hydrant. The system also may include a tool for removing the locking cap from the outlet port and for opening the valve control device.
A third example of a fire hydrant locking device is disclosed in U.S. Pat. No. 5,469,724. The fire hydrant locking device has a cap enclosing the operating nut of the fire hydrant. The cap is secured in place on the top surface of the fire hydrant bonnet by at least one arm extending downwardly over and about the bonnet and extending beyond the fire hydrant barrel mounting flange. The lower end of the arm is attached to the flanges of the barrel and bonnet by bracket and its pad lock so that the cap, arm, and bonnet of the fire hydrant cannot be removed without first removing the fire hydrant locking device. Another locking bracket is received on the outlet cap, of the fire hydrant hose outlets. Chain is passed through each locking bracket encircling the fire hydrant, whereupon the ends of the chain are pad locked together.
As can be seen, there is a need for an improved tamper resistant locking device for a fire hydrant that is simple to install, easy to remove by the fire department using securing fasteners commonly available.